1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Hardware monitoring driver for EMC2305 fan controller 4 * 5 * Copyright (C) 2022 Nvidia Technologies Ltd. 6 */ 7 8 #include <linux/err.h> 9 #include <linux/hwmon.h> 10 #include <linux/i2c.h> 11 #include <linux/module.h> 12 #include <linux/platform_data/emc2305.h> 13 #include <linux/thermal.h> 14 15 static const unsigned short 16 emc2305_normal_i2c[] = { 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d, I2C_CLIENT_END }; 17 18 #define EMC2305_REG_DRIVE_FAIL_STATUS 0x27 19 #define EMC2305_REG_VENDOR 0xfe 20 #define EMC2305_FAN_MAX 0xff 21 #define EMC2305_FAN_MIN 0x00 22 #define EMC2305_FAN_MAX_STATE 10 23 #define EMC2305_DEVICE 0x34 24 #define EMC2305_VENDOR 0x5d 25 #define EMC2305_REG_PRODUCT_ID 0xfd 26 #define EMC2305_TACH_REGS_UNUSE_BITS 3 27 #define EMC2305_TACH_CNT_MULTIPLIER 0x02 28 #define EMC2305_TACH_RANGE_MIN 480 29 30 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \ 31 DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max)) 32 #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \ 33 DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state)) 34 35 /* 36 * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges 37 * equal (poles * 2 + 1). 38 */ 39 #define EMC2305_RPM_FACTOR 3932160 40 41 #define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n)) 42 #define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n)) 43 #define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n)) 44 45 enum emc230x_product_id { 46 EMC2305 = 0x34, 47 EMC2303 = 0x35, 48 EMC2302 = 0x36, 49 EMC2301 = 0x37, 50 }; 51 52 static const struct i2c_device_id emc2305_ids[] = { 53 { "emc2305", 0 }, 54 { "emc2303", 0 }, 55 { "emc2302", 0 }, 56 { "emc2301", 0 }, 57 { } 58 }; 59 MODULE_DEVICE_TABLE(i2c, emc2305_ids); 60 61 /** 62 * @cdev: cooling device; 63 * @curr_state: cooling current state; 64 * @last_hwmon_state: last cooling state updated by hwmon subsystem; 65 * @last_thermal_state: last cooling state updated by thermal subsystem; 66 * 67 * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit 68 * speed feature. The purpose of this feature is to provides ability to limit fan speed 69 * according to some system wise considerations, like absence of some replaceable units (PSU or 70 * line cards), high system ambient temperature, unreliable transceivers temperature sensing or 71 * some other factors which indirectly impacts system's airflow 72 * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is 73 * used for setting low limit for fan speed in case 'thermal' subsystem is configured in 74 * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal' 75 * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm' 76 * attribute. 77 * From other side, fan speed is to be updated in hardware through 'pwm' only in case the 78 * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan 79 * speed will be just stored with no PWM update. 80 */ 81 struct emc2305_cdev_data { 82 struct thermal_cooling_device *cdev; 83 unsigned int cur_state; 84 unsigned long last_hwmon_state; 85 unsigned long last_thermal_state; 86 }; 87 88 /** 89 * @client: i2c client; 90 * @hwmon_dev: hwmon device; 91 * @max_state: maximum cooling state of the cooling device; 92 * @pwm_num: number of PWM channels; 93 * @pwm_separate: separate PWM settings for every channel; 94 * @pwm_min: array of minimum PWM per channel; 95 * @cdev_data: array of cooling devices data; 96 */ 97 struct emc2305_data { 98 struct i2c_client *client; 99 struct device *hwmon_dev; 100 u8 max_state; 101 u8 pwm_num; 102 bool pwm_separate; 103 u8 pwm_min[EMC2305_PWM_MAX]; 104 struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX]; 105 }; 106 107 static char *emc2305_fan_name[] = { 108 "emc2305_fan", 109 "emc2305_fan1", 110 "emc2305_fan2", 111 "emc2305_fan3", 112 "emc2305_fan4", 113 "emc2305_fan5", 114 }; 115 116 static void emc2305_unset_tz(struct device *dev); 117 118 static int emc2305_get_max_channel(const struct emc2305_data *data) 119 { 120 return data->pwm_num; 121 } 122 123 static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) 124 { 125 struct emc2305_data *data = cdev->devdata; 126 size_t len = strlen(cdev->type); 127 int ret; 128 129 if (len <= 0) 130 return -EINVAL; 131 132 /* 133 * Returns index of cooling device 0..4 in case of separate PWM setting. 134 * Zero index is used in case of one common PWM setting. 135 * If the mode is not set as pwm_separate, all PWMs are to be bound 136 * to the common thermal zone and should work at the same speed 137 * to perform cooling for the same thermal junction. 138 * Otherwise, return specific channel that will be used in bound 139 * related PWM to the thermal zone. 140 */ 141 if (!data->pwm_separate) 142 return 0; 143 144 ret = cdev->type[len - 1]; 145 switch (ret) { 146 case '1' ... '5': 147 return ret - '1'; 148 default: 149 break; 150 } 151 return -EINVAL; 152 } 153 154 static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) 155 { 156 int cdev_idx; 157 struct emc2305_data *data = cdev->devdata; 158 159 cdev_idx = emc2305_get_cdev_idx(cdev); 160 if (cdev_idx < 0) 161 return cdev_idx; 162 163 *state = data->cdev_data[cdev_idx].cur_state; 164 return 0; 165 } 166 167 static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) 168 { 169 struct emc2305_data *data = cdev->devdata; 170 *state = data->max_state; 171 return 0; 172 } 173 174 static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state) 175 { 176 int ret; 177 struct i2c_client *client = data->client; 178 u8 val, i; 179 180 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state); 181 182 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX); 183 184 data->cdev_data[cdev_idx].cur_state = state; 185 if (data->pwm_separate) { 186 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val); 187 if (ret < 0) 188 return ret; 189 } else { 190 /* 191 * Set the same PWM value in all channels 192 * if common PWM channel is used. 193 */ 194 for (i = 0; i < data->pwm_num; i++) { 195 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val); 196 if (ret < 0) 197 return ret; 198 } 199 } 200 201 return 0; 202 } 203 204 static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) 205 { 206 int cdev_idx, ret; 207 struct emc2305_data *data = cdev->devdata; 208 209 if (state > data->max_state) 210 return -EINVAL; 211 212 cdev_idx = emc2305_get_cdev_idx(cdev); 213 if (cdev_idx < 0) 214 return cdev_idx; 215 216 /* Save thermal state. */ 217 data->cdev_data[cdev_idx].last_thermal_state = state; 218 ret = __emc2305_set_cur_state(data, cdev_idx, state); 219 if (ret < 0) 220 return ret; 221 222 return 0; 223 } 224 225 static const struct thermal_cooling_device_ops emc2305_cooling_ops = { 226 .get_max_state = emc2305_get_max_state, 227 .get_cur_state = emc2305_get_cur_state, 228 .set_cur_state = emc2305_set_cur_state, 229 }; 230 231 static int emc2305_show_fault(struct device *dev, int channel) 232 { 233 struct emc2305_data *data = dev_get_drvdata(dev); 234 struct i2c_client *client = data->client; 235 int status_reg; 236 237 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS); 238 if (status_reg < 0) 239 return status_reg; 240 241 return status_reg & (1 << channel) ? 1 : 0; 242 } 243 244 static int emc2305_show_fan(struct device *dev, int channel) 245 { 246 struct emc2305_data *data = dev_get_drvdata(dev); 247 struct i2c_client *client = data->client; 248 int ret; 249 250 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel)); 251 if (ret <= 0) 252 return ret; 253 254 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS; 255 ret = EMC2305_RPM_FACTOR / ret; 256 if (ret <= EMC2305_TACH_RANGE_MIN) 257 return 0; 258 259 return ret * EMC2305_TACH_CNT_MULTIPLIER; 260 } 261 262 static int emc2305_show_pwm(struct device *dev, int channel) 263 { 264 struct emc2305_data *data = dev_get_drvdata(dev); 265 struct i2c_client *client = data->client; 266 267 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel)); 268 } 269 270 static int emc2305_set_pwm(struct device *dev, long val, int channel) 271 { 272 struct emc2305_data *data = dev_get_drvdata(dev); 273 struct i2c_client *client = data->client; 274 int ret; 275 276 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX) 277 return -EINVAL; 278 279 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val); 280 if (ret < 0) 281 return ret; 282 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, 283 EMC2305_FAN_MAX); 284 return 0; 285 } 286 287 static int emc2305_set_single_tz(struct device *dev, int idx) 288 { 289 struct emc2305_data *data = dev_get_drvdata(dev); 290 long pwm; 291 int i, cdev_idx, ret; 292 293 cdev_idx = (idx) ? idx - 1 : 0; 294 pwm = data->pwm_min[cdev_idx]; 295 296 data->cdev_data[cdev_idx].cdev = 297 thermal_cooling_device_register(emc2305_fan_name[idx], data, 298 &emc2305_cooling_ops); 299 300 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) { 301 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]); 302 return PTR_ERR(data->cdev_data[cdev_idx].cdev); 303 } 304 /* Set minimal PWM speed. */ 305 if (data->pwm_separate) { 306 ret = emc2305_set_pwm(dev, pwm, cdev_idx); 307 if (ret < 0) 308 return ret; 309 } else { 310 for (i = 0; i < data->pwm_num; i++) { 311 ret = emc2305_set_pwm(dev, pwm, i); 312 if (ret < 0) 313 return ret; 314 } 315 } 316 data->cdev_data[cdev_idx].cur_state = 317 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 318 EMC2305_FAN_MAX); 319 data->cdev_data[cdev_idx].last_hwmon_state = 320 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, 321 EMC2305_FAN_MAX); 322 return 0; 323 } 324 325 static int emc2305_set_tz(struct device *dev) 326 { 327 struct emc2305_data *data = dev_get_drvdata(dev); 328 int i, ret; 329 330 if (!data->pwm_separate) 331 return emc2305_set_single_tz(dev, 0); 332 333 for (i = 0; i < data->pwm_num; i++) { 334 ret = emc2305_set_single_tz(dev, i + 1); 335 if (ret) 336 goto thermal_cooling_device_register_fail; 337 } 338 return 0; 339 340 thermal_cooling_device_register_fail: 341 emc2305_unset_tz(dev); 342 return ret; 343 } 344 345 static void emc2305_unset_tz(struct device *dev) 346 { 347 struct emc2305_data *data = dev_get_drvdata(dev); 348 int i; 349 350 /* Unregister cooling device. */ 351 for (i = 0; i < EMC2305_PWM_MAX; i++) 352 if (data->cdev_data[i].cdev) 353 thermal_cooling_device_unregister(data->cdev_data[i].cdev); 354 } 355 356 static umode_t 357 emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) 358 { 359 int max_channel = emc2305_get_max_channel(data); 360 361 /* Don't show channels which are not physically connected. */ 362 if (channel >= max_channel) 363 return 0; 364 switch (type) { 365 case hwmon_fan: 366 switch (attr) { 367 case hwmon_fan_input: 368 return 0444; 369 case hwmon_fan_fault: 370 return 0444; 371 default: 372 break; 373 } 374 break; 375 case hwmon_pwm: 376 switch (attr) { 377 case hwmon_pwm_input: 378 return 0644; 379 default: 380 break; 381 } 382 break; 383 default: 384 break; 385 } 386 387 return 0; 388 }; 389 390 static int 391 emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) 392 { 393 struct emc2305_data *data = dev_get_drvdata(dev); 394 int cdev_idx; 395 396 switch (type) { 397 case hwmon_pwm: 398 switch (attr) { 399 case hwmon_pwm_input: 400 /* If thermal is configured - handle PWM limit setting. */ 401 if (IS_REACHABLE(CONFIG_THERMAL)) { 402 if (data->pwm_separate) 403 cdev_idx = channel; 404 else 405 cdev_idx = 0; 406 data->cdev_data[cdev_idx].last_hwmon_state = 407 EMC2305_PWM_DUTY2STATE(val, data->max_state, 408 EMC2305_FAN_MAX); 409 /* 410 * Update PWM only in case requested state is not less than the 411 * last thermal state. 412 */ 413 if (data->cdev_data[cdev_idx].last_hwmon_state >= 414 data->cdev_data[cdev_idx].last_thermal_state) 415 return __emc2305_set_cur_state(data, cdev_idx, 416 data->cdev_data[cdev_idx].last_hwmon_state); 417 return 0; 418 } 419 return emc2305_set_pwm(dev, val, channel); 420 default: 421 break; 422 } 423 break; 424 default: 425 break; 426 } 427 428 return -EOPNOTSUPP; 429 }; 430 431 static int 432 emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) 433 { 434 int ret; 435 436 switch (type) { 437 case hwmon_fan: 438 switch (attr) { 439 case hwmon_fan_input: 440 ret = emc2305_show_fan(dev, channel); 441 if (ret < 0) 442 return ret; 443 *val = ret; 444 return 0; 445 case hwmon_fan_fault: 446 ret = emc2305_show_fault(dev, channel); 447 if (ret < 0) 448 return ret; 449 *val = ret; 450 return 0; 451 default: 452 break; 453 } 454 break; 455 case hwmon_pwm: 456 switch (attr) { 457 case hwmon_pwm_input: 458 ret = emc2305_show_pwm(dev, channel); 459 if (ret < 0) 460 return ret; 461 *val = ret; 462 return 0; 463 default: 464 break; 465 } 466 break; 467 default: 468 break; 469 } 470 471 return -EOPNOTSUPP; 472 }; 473 474 static const struct hwmon_ops emc2305_ops = { 475 .is_visible = emc2305_is_visible, 476 .read = emc2305_read, 477 .write = emc2305_write, 478 }; 479 480 static const struct hwmon_channel_info *emc2305_info[] = { 481 HWMON_CHANNEL_INFO(fan, 482 HWMON_F_INPUT | HWMON_F_FAULT, 483 HWMON_F_INPUT | HWMON_F_FAULT, 484 HWMON_F_INPUT | HWMON_F_FAULT, 485 HWMON_F_INPUT | HWMON_F_FAULT, 486 HWMON_F_INPUT | HWMON_F_FAULT), 487 HWMON_CHANNEL_INFO(pwm, 488 HWMON_PWM_INPUT, 489 HWMON_PWM_INPUT, 490 HWMON_PWM_INPUT, 491 HWMON_PWM_INPUT, 492 HWMON_PWM_INPUT), 493 NULL 494 }; 495 496 static const struct hwmon_chip_info emc2305_chip_info = { 497 .ops = &emc2305_ops, 498 .info = emc2305_info, 499 }; 500 501 static int emc2305_identify(struct device *dev) 502 { 503 struct i2c_client *client = to_i2c_client(dev); 504 struct emc2305_data *data = i2c_get_clientdata(client); 505 int ret; 506 507 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID); 508 if (ret < 0) 509 return ret; 510 511 switch (ret) { 512 case EMC2305: 513 data->pwm_num = 5; 514 break; 515 case EMC2303: 516 data->pwm_num = 3; 517 break; 518 case EMC2302: 519 data->pwm_num = 2; 520 break; 521 case EMC2301: 522 data->pwm_num = 1; 523 break; 524 default: 525 return -ENODEV; 526 } 527 528 return 0; 529 } 530 531 static int emc2305_probe(struct i2c_client *client) 532 { 533 struct i2c_adapter *adapter = client->adapter; 534 struct device *dev = &client->dev; 535 struct emc2305_data *data; 536 struct emc2305_platform_data *pdata; 537 int vendor; 538 int ret; 539 int i; 540 541 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 542 return -ENODEV; 543 544 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR); 545 if (vendor != EMC2305_VENDOR) 546 return -ENODEV; 547 548 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 549 if (!data) 550 return -ENOMEM; 551 552 i2c_set_clientdata(client, data); 553 data->client = client; 554 555 ret = emc2305_identify(dev); 556 if (ret) 557 return ret; 558 559 pdata = dev_get_platdata(&client->dev); 560 if (pdata) { 561 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE) 562 return -EINVAL; 563 data->max_state = pdata->max_state; 564 /* 565 * Validate a number of active PWM channels. Note that 566 * configured number can be less than the actual maximum 567 * supported by the device. 568 */ 569 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX) 570 return -EINVAL; 571 data->pwm_num = pdata->pwm_num; 572 data->pwm_separate = pdata->pwm_separate; 573 for (i = 0; i < EMC2305_PWM_MAX; i++) 574 data->pwm_min[i] = pdata->pwm_min[i]; 575 } else { 576 data->max_state = EMC2305_FAN_MAX_STATE; 577 data->pwm_separate = false; 578 for (i = 0; i < EMC2305_PWM_MAX; i++) 579 data->pwm_min[i] = EMC2305_FAN_MIN; 580 } 581 582 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data, 583 &emc2305_chip_info, NULL); 584 if (IS_ERR(data->hwmon_dev)) 585 return PTR_ERR(data->hwmon_dev); 586 587 if (IS_REACHABLE(CONFIG_THERMAL)) { 588 ret = emc2305_set_tz(dev); 589 if (ret != 0) 590 return ret; 591 } 592 593 for (i = 0; i < data->pwm_num; i++) { 594 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), 595 data->pwm_min[i]); 596 if (ret < 0) 597 return ret; 598 } 599 600 return 0; 601 } 602 603 static void emc2305_remove(struct i2c_client *client) 604 { 605 struct device *dev = &client->dev; 606 607 if (IS_REACHABLE(CONFIG_THERMAL)) 608 emc2305_unset_tz(dev); 609 } 610 611 static struct i2c_driver emc2305_driver = { 612 .class = I2C_CLASS_HWMON, 613 .driver = { 614 .name = "emc2305", 615 }, 616 .probe_new = emc2305_probe, 617 .remove = emc2305_remove, 618 .id_table = emc2305_ids, 619 .address_list = emc2305_normal_i2c, 620 }; 621 622 module_i2c_driver(emc2305_driver); 623 624 MODULE_AUTHOR("Nvidia"); 625 MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); 626 MODULE_LICENSE("GPL"); 627